How do I measure time taken per namepace to run clojure tests?

Question

Is there a way to instrument the code and find out how much time each namespace takes or the only way forward is to use fixtures?

What is a good approach for solving such a problem?

Answer 1

Your suggestion of using run-tests over a list of namespaces will work.

Here is a function I wrote to loop ever namespaces in the repl, reload them all, then run tests for each ns. You could modify the code for your purpose. You would have to add code to capture the starting/ending time and print the elapsed time for each ns.

As the docstring says, this code assumes the namespaces are set up to look like:

    myproj.myfeat      ; main namespace
tst.myproj.myfeat      ; testing namespace

so just strip out or modify the part with (symbol (str "tst." curr-ns)) as required for your setup. You'll probably want to use all-ns to get a listing of all namespaces, then either remove or ignore the non-testing namespaces. Good luck!

(defn ^:deprecated ^:no-doc test-all
  "Convenience fn to reload a namespace & the corresponding test namespace from disk and
  execute tests in the REPL.  Assumes canonical project test file organization with
  parallel src/... & test/tst/... directories, where a 'tst.' prefix is added to all src
  namespaces to generate the cooresponding test namespace.  Example:

    (test-all 'tupelo.core 'tupelo.csv)

  This will reload tupelo.core, tst.tupelo.core, tupelo.csv, tst.tupelo.csv and
  then execute clojure.test/run-tests on both of the test namespaces."
  [& ns-list]
  (let [test-ns-list (for [curr-ns ns-list]
                       (let [curr-ns-test (symbol (str "tst." curr-ns))]
                         (println (str "testing " curr-ns " & " curr-ns-test))
                         (require curr-ns curr-ns-test :reload)
                         curr-ns-test))
        ]
    (println "-----------------------------------------------------------------------------")
    (apply clojure.test/run-tests test-ns-list)
    (println "-----------------------------------------------------------------------------")
    (newline)
    ))

Answer 2

You can use eftest's :test-warn-time to measure timing of tests per NS.

Once added, you'll see colored (not shown) output like this to indicate a slow test:

LONG TEST in foo-api.handlers.foo-test during :clojure.test/once-fixtures
Test took 12.300 seconds seconds to run